1. Field of the Invention
This invention relates to a water-sealed structure of a roof.
2. Description of the Prior Art
The present inventor invented and filed the invention in Jap. Pat. Appln. No. 69995/1984 (Jap. Pat. Laid-Open No. 215963/1985) in order to prevent a so-called "water leakage" generated by an accumulation of snow on a roof in a cold weather district such as a snow country and further to prevent leakage of water by applying a water-proof plate and the like. That is, in the prior art invention, as shown in FIG. 31, it is constructed such that a lower inner material (12) is arranged on a supporting member (11) such as a main house, an upper inner layer material (21) is arranged and fixed to a fixing member (25) comprised of a rafter (19) fixed on the lower inner layer material (12) and of a fixing fitting (16) or the like, an air layer (22) is formed between the lower inner layer material (12) and the upper inner layer material (21), a roof plate (23) is placed on the upper inner layer material (21), a water-proof plate (14) is set on the lower inner layer material (12), both side edges (14a), (14a) of the water-proof plate (14) are pressed and held with the lower inner layer material (12) and the fixing member (25), and a drain port adjacent to eaves of the water-proof plate (14) and to cause the air layer (22) to be opened out of the roof.
However, the aforesaid invention has a disadvantage that rain water flowing down a metallic roof surface is accumulated to be stopped by strong wind under an abnormal environmental condition in which heavy rain fall in typhoon and local heavy rail fall together with a continuous strong wind occurs, resulting in that an edge part of the roof panel shows a flooding condition and then the rain water overflows the edge part to enter a room. That is, the overflown rain water enters from engaging claws (19a) of a metallic rafter (19) in FIG. 31 in a direction indicated by an arrow (A) and shows a problem that it enters from between the rised parts (14a) of the adjoining water-proof plates into a room.
In recent years, due to a trend of multi-versions of design and raw material for a roofing, some tiles or natural slates only used for ornamental purpose in a parapet in a building or the like are used as materials for a roof of a building. The tiles or natural slates have a water-proof function as a roofing material. However, under such a condition as one in which a strong wind may act at a high location of a top part of a building, a rain water-proof characteristic is not sufficient and so a roof structure having a sufficient and safe rain water-proof characteristic even under an application of these roof materials is requested.
It is frequently found that a wall structure of a building in particular a roof backing is of an iron backing. In addition, it is also found that the roof backing is composed of iron together with air-bubbled light-weight concrete (hereinafter called as ALC) and in case of a building of a medium-size or lower, the concrete surface (hereinafter called as RC) of which level is adjusted with mortar on RC is applied as a roof backing.
It is usually acknowledged that the building worked with this ALC or RC of a backing material hardly produces an accident of water leakage. However, in a practical work, it merely shows that ALC and RC have a water-absorbing characteristic and in turn they may keep water in it and may not pass it easily, so that water is hardly immersed into a room. Since the accident of water leakage in a building of ALC or RC is advanced as a crack caused by water in the backing is generated to cause the building itself to be weakened and influence against its structural strength. Once the water leakage occurs, a specifying of the water leakage position is quite difficult and an entire repairing of the leaked location is needed. It accompanies with a freezing disaster at a cold weather district and this becomes more severe problem.